RTL-SDR

The RTL2832U & R820T is a software defined radio/tuner USB dongle capable of receiving 24 - 1766 MHz radio signals, including DVB-T.

You can use it with e.g. a Raspberry Pi or any other Debian based Linux to listen to FM radio.

Installation

Building from sources is not necessary any more...

apt-get install rtl-sdr

Configure amixer

Audiomixer has different controls depending on the operating system version and configuration:

Version 1

Audio controls:

amixer controls

numid=3,iface=MIXER,name='PCM Playback Route'
numid=2,iface=MIXER,name='PCM Playback Switch'
numid=1,iface=MIXER,name='PCM Playback Volume'

Set jack (analog) output:

amixer cset numid=3 1

Set HDMI output:

amixer cset numid=3 2

Set audio volume:

amixer sset "PCM" 90%

Version 2

Audio controls:

amixer controls

numid=4,iface=MIXER,name='Master Playback Switch'
numid=3,iface=MIXER,name='Master Playback Volume'
numid=2,iface=MIXER,name='Capture Switch'
numid=1,iface=MIXER,name='Capture Volume'

Enable audio:

amixer cset numid=4 1

Set volume at 76%

amixer cset numid=3 50000

Verify:

amixer

Simple mixer control 'Master',0
 Capabilities: pvolume pswitch pswitch-joined
 Playback channels: Front Left - Front Right
 Limits: Playback 0 - 65536
 Mono:
 Front Left: Playback 50020 [76%] [on]
 Front Right: Playback 50020 [76%] [on]

Test aplay

You should hear a kitten miaw...

aplay /usr/share/scratch/Media/Sounds/Animal/Kitten.wav

Listen to FM Radio

Tune into an FM radio station:

rtl_fm -f 91.7e6 -s 200000 -r 48000 |aplay -r 48000 -f S16_LE

Other applications

• ADSB tracking
• gqrx

External links

• https://www.rtl-sdr.com/rtl-sdr-quick-start-guide/